EDIT: Firefox leads you to nowhere, it is too big. I once proposed this idea to Torproject and they seems uninterested because of the lack of scripting and quirk mode! You can try dillo and see how it is made elegantly(imho) enough to safeguard all the Web2.0 privacy cracks that not even developers want to give a shit. It would be a great "weapon" to sort of compete with Tor, if it is forked and reviewed by i2p developers, then it will be a useful application for us.